[国嵌攻略][155][I2C用户态驱动设计]

/********************************************************************
*头文件
*********************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>

/********************************************************************
*宏定义
*********************************************************************/
#define I2C_RDWR 0x0707   //I2C读写命令

/********************************************************************
*类型定义
*********************************************************************/
typedef struct i2c_msg{
    unsigned short addr;    //设备地址
    unsigned short flags;   //读写标志
    unsigned short len;     //消息长度
    unsigned char  *buf;    //消息内容
}IIC_MSG;

typedef struct i2c_rdwr_ioctl_data{
    struct i2c_msg *msgs;   //消息指针
    unsigned int nmsgs;     //消息数量
}IIC_DATA;

/********************************************************************
*名称:main
*参数:
*    none
*返回:
*    none
*功能:主函数
*********************************************************************/
int main(){
    //打开设备文件
    int fd;
    
    fd = open("/dev/i2c-0", O_RDWR);
    
    //构造写入消息
    IIC_DATA wrData;
    
    wrData.msgs = (IIC_MSG *)malloc(1*sizeof(IIC_MSG));
    
    wrData.msgs[0].addr  = 0x50;   //注意设备地址为0b01010000,但是芯片手册地址为0b10100000
    wrData.msgs[0].flags = 0;
    wrData.msgs[0].len   = 2;
    wrData.msgs[0].buf = (unsigned char *)malloc(2*sizeof(unsigned char));
    wrData.msgs[0].buf[0] = 0;
    wrData.msgs[0].buf[1] = 123;
    
    wrData.nmsgs = 1;
    
    //写入消息数据
    ioctl(fd, I2C_RDWR, (unsigned long)(&wrData));
    printf("wrData is %d\n", wrData.msgs[0].buf[1]);
    
    //释放写入消息
    free(wrData.msgs[0].buf);
    free(wrData.msgs);
    
    //构造读取消息
    IIC_DATA rdData;
    
    rdData.msgs = (IIC_MSG *)malloc(2*sizeof(IIC_MSG));
    
    rdData.msgs[0].addr  = 0x50;
    rdData.msgs[0].flags = 0;
    rdData.msgs[0].len   = 1;
    rdData.msgs[0].buf = (unsigned char *)malloc(1*sizeof(unsigned char));
    rdData.msgs[0].buf[0] = 0;
    
    rdData.msgs[1].addr  = 0x50;
    rdData.msgs[1].flags = 1;
    rdData.msgs[1].len   = 1;
    rdData.msgs[1].buf = (unsigned char *)malloc(1*sizeof(unsigned char));
    rdData.msgs[1].buf[0] = 0;
    
    rdData.nmsgs = 2;
    
    //读取消息数据
    ioctl(fd, I2C_RDWR, (unsigned long)(&rdData));
    printf("rdData is %d\n", rdData.msgs[1].buf[0]);
    
    //释放读取消息
    free(rdData.msgs[0].buf);
    free(rdData.msgs[1].buf);
    free(rdData.msgs);
    
    //关闭设备文件
    close(fd);
}